This invention pertains to zippers, and especially to plastic zippers which are used to control access, to open and close, e.g. plastic bags or other packaging structures, thus temporarily closing off access, and also allowing access, as appropriate, to the contents of the package. Access to contents of the bag is prevented when the zipper is closed, and access to contents of the bag is enabled when the zipper is open.
In a broad sense, the invention can pertain to any use of slider-based plastic zippers which control access to contents of a package or other container, or other controlled-access space.
In some instances, the zipper elements may be disposed inside a closed compartment of the container/bag/package, and a second closure/seal, intended to be a single-use closure/seal, is used in addition to the re-closable, re-openable closure/seal affected by the zipper, thus closing in the entirety of the zipper within the space enclosed inside the bag. In such structure, once the single-use seal/closure has been breached, opened, e.g. by the consumer of the bag contents, thus exposing the zipper, the re-closable zipper is subsequently used to provide temporary and re-closable access, namely intermittent access, to the contents of the container/package/bag while otherwise sealing the container/package/bag, for example to preserve freshness and/or quality of the product contained within the container/package/bag.
In early commercial versions of plastic bags which have zippers, which early versions are still commercially available, the zipper is defined by first and second facing interlocking rails on facing or overlapping panels of the plastic bag e.g. while the bag is being fabricated. Such interlocking rails are in facing relationship with each other, typically at the top of the bag. Typically, such interlocking rails extend the full respective dimension, for example the width or the length, of the bag. The user presses and holds the interlocking rails against each other, and advances that held pressure along the length of the interlocking rails, namely across the width, or the length, of the bag, whereby the interlocking rails are pressed into a lacking engagement with each other along the length of the zipper, thus to seal closed the facing interlocking rails of the zipper at the facing panels.
Such plastic zippers have now come into commercial use in combination with a variety of products which are packaged in flexible plastic packaging, for example various types of food, whether sold through grocery stores or convenience stores or as ready-to-eat products/food sold through e.g. a restaurant, a café, or the like.
One of the challenges accompanying such early versions of plastic zippers on plastic bags is/was the need to apply the necessary amount of pressure to the pair of interlocking rails, progressively along the entirety of the full length of the zipper in order to affect closure of the zipper along the full length of the zipper. If the user does not apply the necessary level of pressure at all points along the length of the interlocking rails, some portion of the length of the zipper can be left open, unsealed, whereby the contents of the bag are not protected from leakage out of the bag, or from infiltration of unwanted materials into the bag, or from infiltration of ambient conditions into the bag, which may adversely affect the contents of the bag. Similarly, if the interlocking rails are not properly laterally aligned with each other, no amount of pressure will provide the desired closure/seal which is the purpose of having a plastic zipper.
So there are some challenges associated with using, attempting to use, zippers where achieving a sealed closure of the zipper relies on the user being able to properly align the interlocking rails, and to apply a sufficient amount of pressure along the full lengths of such properly aligned interlocking rails of the zipper.
In a later, and known, commercially-available version of such plastic bags which can be “zipped” closed, a “slider”, as a second and distinct element, not part of the container/bag, itself, is mounted to, and straddles, the two sides of the bag at facing interlocking rails. As the user pulls the slider along the interlocking rails in a first direction, the slider engages both of the interlocking rails, performing the tasks of keeping the interlocking rails properly aligned with each other, and applying the appropriate interface and/or pressure between the facing interlocking rails, progressively along the length of the zipper as the slider is moved along the length of the zipper, whereby the facing interlocking rails are progressively sealed closed against each other, thus progressively sealing the bag closed at the zipper as the slider progresses along the length of the zipper. Such closure/seal prevents access to the contents of the bag so long as the zipper remains closed/sealed, as well as preventing spillage or leakage of the contents from the bag.
So a plastic zipper which uses a slider is both easier to operate, and more reliable in actually closing the full length of the zipper, than a zipper which relies on the user for interlocking rail alignment and for applying the proper amount of pressure along the full length of the zipper.
But the ease of closing the bag applies equally well to ease of opening the bag at the zipper, thus unsealing and opening the bag, by pulling the slider in the opposing direction, whereby the slider releases, re-opens the closure/seal and the bag is opened at the zipper, allowing access to the contents of the bag. Thus, just as with the non-slider version of plastic zippers, slider-based plastic zippers provide the ability to seal the bag closed, then re-open/unseal the bag. Such bag can be sealed, and re-opened, a plurality of times using a single slider on such plastic zipper.
Whether the zipper consists only of the facing interlocking rails, or includes a slider as a separate element, either way, the process of opening the zipper and accessing the contents of the bag is easy enough that a child, or other unauthorized individual, has the ability and/or strength to open the bag and access the contents of the bag.
While the original such type of locking bags, without separate slider element, is still available, and less expensive than bags which use the separate slider, bags with a separate slider seem to be easier to use. And slider bags provide greater assurance of in fact achieving a full seal along the full length of the zipper. Depending at least in part on strength and dexterity of the user, and diligence of the user of a bag where a slider is not used, slider bags may provide greater assurance that the zipper is in fact fully closed and sealed along a continuous and full length of the zipper. Especially where the cost of the bag is trivial relative to the cost of the contemplated/expected contents of the bag, bags having the slider may be more commonly used in the commercial market than zipper bags which do not employ a plastic zipper.
As more and more types of products are being packaged in bags having closures which use a slider on a plastic zipper, there arises the challenge of how to keep the bag sealed closed, while also enabling opening of the bag for access to the bag contents by an authorized user. For example, where a hazardous or toxic product, such as, for example and without limitation, dish soap or laundry soap, or a marijuana product, or a pesticide product, or a fungicidal product, or a fertilizer product, is packaged and/or sold in such a bag, there is a need to prevent unauthorized individuals, such as a child, from accessing the hazardous or toxic product, or controlled substance.
In bags which do not use a slider, the e.g. child simply tugs, pulls on the walls of the closed/sealed bag enough that, if the child is strong enough, the child eventually gets the bag open and thus has access to such hazardous contents.
Where a slider is used, gaining access to bag contents is even easier because the slider is easier to use. All the e.g. child has to do is to apply a pull force to the slider, and continue pulling until the child gets the pull force going in the right direction to move the slider, thus to open the bag.
Thus, while a bag which does not use a slider poses a less-than-desirable barrier to a child, the typical slider poses even less of a barrier to a child's ability to access the product inside the bag. And yet it is the slider-type re-openable closure mechanism which provides the easiest access to the bag contents for an authorized user, as well as the greatest assurance that the bag has, in fact, been fully closed/sealed at the zipper.
In some embodiments, a slider-based zipper can be used on facing flexible plastic panels where the flexible plastic panels are mounted to one or more other elements of the package/container structure which are generally considered to be inflexible, for example such facing flexible plastic panels may be mounted to hard plastic, plastic or other flexible laminate, or cardboard, or corrugated board, or natural or manufactured wood products, or metal portions of a container/package, optionally functioning as flexible extensions of such elements. Such embodiments encounter the same challenges as mentioned above, relating to interlocking rail alignment, closing pressure, and preventing unauthorized access to the product contained in such package/container.
Thus it would be desirable to provide a way to limit access to the product-holding compartment of a package or other structure which is opened and closed by a plastic zipper.
It would further be desirable to provide an access-controlling mechanism, for example and without limitation, a locking mechanism, for use at the zipper on a plastic bag.
It would also be desirable to provide such access-controlling mechanism as a locking mechanism for use on a container/receptacle/package/bag which uses a plastic zipper with a slider to close, and to then re-open, such container, at will, in order to deny unauthorized access to the contents of the container such as to a child or other physically or mentally or otherwise developmentally-challenged/disabled individual, while also allowing, enabling ready access to authorized individuals.
Such mechanism should desirably make it difficult, preferably impossible, for a child or other physically or mentally-challenged user to open the bag or other container, thus to gain access to the contents of the bag, through the zipper, while allowing access to an authorized user.